Water impurity analysis method

ABSTRACT

To determine the total organic carbon content of a flowing liquid in a continuous process, water and oxidizing agents enter lower ports in a continuous column and flow upwardly along a helical path with air gaps as they are mixed. The helical reaction path is formed by a helical glass cylinder between an ultraviolet lamp and outer wall of a continuous glass tube to cause rapid motion of the liquid. An ultraviolet lamp extends downwardly through the center of the column so that the outer confining surface of the helical path is the outer surface of the ultraviolet lamp, causing the liquid to move rapidly in intimate contact with the ultraviolet lamp to receive intense radiation. An air gap permits escape of air and reduces bubble size to reduce plug flow.

REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.09/049,629 filed Mar. 27, 1998, which is a divisional of U.S.application Ser. No. 08/634,007 filed Apr. 15, 1996, now U.S. Pat. No.5,733,789, which is a divisional of U.S. application Ser. No. 08/386,699filed Feb. 10, 1995, now U.S. Pat. No. 5,531,961 entitled WATER IMPURITYANALYZER.

BACKGROUND OF THE INVENTION

This invention relates to apparatuses and methods for sensing impuritiesin water.

It is known to determine the amount of organic carbon in water beingtested by oxidizing the organic carbon in a sample of water andmeasuring the amount of carbon dioxide obtained by such oxidation. Oneclass of techniques and apparatus for measuring organic carbon arecontinuous in operation. In a continuous process, the organic carbon inwater is oxidized as the water flows through an ultraviolet reactor andthe amount of water flowing through the reactor is measured. The carbondioxide formed by oxidizing the organic carbon in the measured water isalso measured to provide an indication of the amount of organic carbonin a unit of water.

In a prior art continuous process for measuring the total organiccontent of water, each of the stages for oxidation of carbon has its ownultraviolet source and may have its own source of oxidizing agent and/oroxygen or there is a single ultraviolet source in a single stage.

The prior art apparatuses and techniques for measuring the total organiccarbon content of water has several disadvantages, such as for example:(1) there is a tendency for some of the carbon dioxide to escape beforeit is collected and measured; (2) in those embodiments in which severalultraviolet light sources are used, the cost is high; and (3) it isdifficult to obtain complete oxidation of the organic carbon.

Certain prior art patents disclose the flow of water in a helical pathadjacent to an ultraviolet lamp for the purpose of sterilization orpurification of water. However, these patents do not need residencechambers that interrupt the helical flow or bubble-size reductionprovisions nor are they carbon measuring apparatus. They are notanalytical instruments at all and are not concerned with thecompleteness of oxidation of carbon as an approach to measuring carboncontent.

Some such patents and patent applications are U.S. Pat. Nos. 4,008,045;5,675,153; 5,069,885; 2,501,290; Canadian Patent 674,555; Europeanpatent application 0202891; German Offenlegungsschrift 2,327,084; andFrench Patent 1,278,161.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the invention to provide a novelapparatus and method for analyzing the organic carbon content ofliquids.

It is a still further object of the invention to provide a noveltechnique for oxidizing carbon within liquids.

It is a still further object of the invention to provide a measuringtechnique and apparatus for total carbon analysis of water.

It is a still further object of the invention to provide a technique andapparatus for increasing the oxidation of carbon in minimum space and atminimum cost.

It is a still further object of the invention to provide a technique andapparatus that obtains a balance between the time necessary for mixingoxidizers with water containing organic compounds with the amount oftime provided for ultraviolet irradiation and distance from the sourceof ultraviolet radiation so as to more effectively provide a totalorganic carbon measuring technique.

It is a still further object of the invention to provide a total organiccarbon measuring technique which maximizes the recovery of gases formedby the oxidation of organic carbon in a liquid.

It is a still further object of the invention to provide a novelapparatus and method for determining the absence of liquid in a system.

It is a still further object of the invention to minimize theinteraction between a plurality of reaction stages as the liquid and gascomponents rise through the ultraviolet reactor assembly.

It is a still further object of the invention to provide a novel methodand apparatus for balancing the amount of oxygen, oxidizers andunreacted organic carbon to improve efficiency.

It is a still further object of the invention to provide an organiccarbon analyzer that is easy to manufacture and maintain and permitseasy variation in the construction of the column to reduce the cost andimprove its ability to perform under different circumstances.

It is still a further object of this invention to provide an organiccarbon analyzer that controls the mixing of the carbon carrying liquid,the oxidizers and the gas to provide efficient oxidation of the carbonby moving the mixture along a single upwardly extending helix of shortenough height to be economical.

It is a still further object of the invention to provide a total organiccarbon analyzer that controls the formation of gas bubbles to obtainefficient fluid mixing and oxidation.

In accordance with the above and further objects of the invention, wateris pumped through an apparatus for removing inorganic carbon and fromthere into a reactor where the water is mixed with an oxidizing agentand a carrier gas containing from zero percent to 100 percent oxygensuch as air. The mixture is exposed to ultraviolet light, and in oneembodiment, the gas oxidizing agent and oxygen are mixed in a pluralityof residence time stages separated by stages in which it flows closelyadjacent to a source of ultraviolet light to catalyze the oxidation oforganic carbon. In another embodiment, a continuous helix with noresidence chambers is used which surprisingly provides adequate mixingand exposure to maintain efficiency with a limited height.

The apparatus includes an elongated ultraviolet lamp which fits throughthe center of an elongated reactor chamber. In one embodiment, themixture flows through a brief turbulent section into a residence chamberadjusted in length and width to accommodate the time needed for mixingand removal of gases, followed by flowing through a small curvilinearpath through which the liquid flows in a helical path adjacent to andaround the central ultraviolet lamp for intense radiation withultraviolet light. In the other embodiment the mixture flows from theturbulent section into a continuous helix that provides for the escapeof air from larger bubbles.

In the one embodiment the two types of stages are repeated with thelarger volume residence chambers providing time during which mixingreaction and separation of gas and water occurs. These residencechambers become shorter in length in a manner that balances the need forthe separation and mixing time at slow linear rate of movements ofliquid and with the helical sections providing fast linear movementalong the helical path for intense irradiation and rapid movement nearthe lamp. This provides efficient combinations of irradiation, mixingreaction and separation of gas to provide total oxidation along thesmallest unbroken path. The apparatus is economical because it includesa single ultraviolet lamp and provides complete capture of gases becauseof the unbroken path which obtains total oxidation.

In the other embodiment, the single continuous helical path surroundingthe ultraviolet light has provisions in it for causing the mixing to behorizontal for efficient contact with the ultraviolet lamp and efficientmovement of the combination of gas, oxidizing agent and liquid carryingorganic carbon upwardly to the extent that residence chambers are notneeded and a single upwardly extending helical path is sufficient.Horizontal mixing is aided by control of the size of gas bubbles. It wasdiscovered that as the mixture of gas, oxidizing agent and liquid movedupwardly, smaller bubbles would coalesce into large bubbles that causeplug flow. The larger bubbles move more slowly and smaller bubblesfurther coalesce into it aggrevating the difficulty and reducing thehorizontal mixing of the liquid. This plug flow led workers to usemultiple stages calling for multiple lamps and duplicate other parts toachieve adequate oxidation of the carbon. The two embodiments, one usingretention chambers and the other bubble control, solve this probleminexpensively.

In a preferred embodiment, air was permitted to move upwardly in avertical direction, leaking from the helical path while the downwardfalling of liquid from the helical path was substantially eliminated orgreatly reduced by surface tension in the small air gaps to control thesize of bubbles while avoiding vertical mixing. The use of hightemperature materials at an elevated temperature further increased theefficiency of this process.

From the above description, it can be understood that the carbonanalyzing apparatus and technique of this invention has severaladvantages, such as: (1) it is economical to construct and includes onlyone ultraviolet lamp; (2) it reduces the loss of gases to be measuredbecause it is a single element extending upwardly so as to collect allthe desirable gas at the top of a single closed path; (3) it providesappropriate balances between mixing of oxidizing agents, carrier gas andsample, reaction time, irradiation and the appropriate intensities ofturbulance suitable for the carbon content of the water; (4) itminimizes the interaction between the reaction stages as the liquid andgas components rise through the ultraviolet reactor assembly; (5) itpermits the addition of reagents of intermediate points in the reaction;(6) it permits adjustment for other compounds such as sodium chloridethat provide ions resulting in side reactions that compete with thecarbon reaction; and (7) it permits ease of manufacture and maintenanceand provides easy variation of the construction of the column to reducethe cost and improve its ability to perform under differentcircumstances.

SUMMARY OF THE DRAWINGS

The above noted and other features of the invention will be betterunderstood from the following detailed description when considered withreference with the accompanying drawings, in which:

FIG. 1 is a block diagram of an embodiment of analyzer in accordancewith the invention;

FIG. 2 is a schematic diagram of a system for total analysis of theorganic carbon content of liquids in accordance with the invention;

FIG. 3 is an elevational view of an instrument panel and instrumentuseful in the embodiment of FIGS. 1 and 2;

FIG. 4 is a simplified fragmentary perspective view partly broken awayshowing an embodiment of UV reactor;

FIG. 5 is a longitudinal sectional view of the reactor of FIG. 4;

FIG. 6 is a longitudinal section view of a portion of the embodiment ofFIG. 5;

FIG. 7 is a transverse sectional view of a portion of the embodiment ofFIG. 5;

FIG. 8 is a sectional view of a portion of the embodiment of FIG. 5;

FIG. 9 is a longitudinal sectional view of still another portion of theembodiment of FIG. 5;

FIG. 10 is an end view of a fitting useful in the embodiment of FIG. 5;

FIG. 11 is a side elevational view of an outer shell used for the UVreactor of FIG. 5;

FIG. 12 is a sectional view of an outer casing of the embodiment of FIG.5;

FIG. 13 is a side elevational view of an ultraviolet lamp useful in theembodiments in FIGS. 1-3;

FIG. 14 is a side elevational view of a liquid detector useful in theembodiment of FIGS. 1-13;

FIG. 15 is an end elevational view of the liquid detector of FIG. 14;

FIG. 16 is a top view of the liquid detector of FIG. 14;

FIG. 17 is an exploded side elevational view of the liquid detector ofFIG. 14 with a thermistor shown exploded away from it;

FIG. 18 is a fragmentary, elevational view of another embodiment ofreactor; and

FIG. 19 is a sectional view of a portion of the embodiment of FIG. 19.

DETAILED DESCRIPTION

In FIG. 1, there is shown a block diagram of a continuous process,total-oxidation of carbon system 10 having a water sample source 12, anadditive source 14, a carrier gas source 16 which may be air, a reactorsystem 18 and a detector system 20. In this system, a sample of water ispumped from a source of water 12 into the reactor system 18, mixed withadditives from the source 14 and with air from the source 16 for mixingthe additives and water. The organic carbon is oxidized in the reactorsystem 18 and measured in the detection system 20. Additives are pumpedto water source 12 through conduit 15 for processing water prior tooxidation.

After processing, the water is pumped: (1) through the conduit 22 intothe reactor system 18 which communicates between the source of water andthe reactor system 18; (2) additives are pumped from the additive source14 to the reactor system 18 through the conduit 26 which communicateswith both of them; and (3) the reactor system 18 oxidizes the organiccarbon within the sample of water and causes the resulting carbon gasesto flow through a conduit 34 to the detection system 20 which detectsand measures the amount of carbon gases resulting from the oxidation oforganic carbon in the gas. This measurement is transmitted through acable 48 to and utilized within a computer 44, which also controls thepumps and the like with which it communicates, to calculate the amountof organic carbon and transmit these values to the display 46 forprinting and visualization.

The air source 16 supplies carrier gas, for example, air through theconduit 28 to the reactor 18 with which it communicates for oxidation ofthe organic carbon and also supplies air through the conduits 24 to thewater supply system 12 and to the detector system 20 through theconduits 30 and 32 which communicates between them for uses to explainedhereinafter. Purge gas from the detection system 20 is applied to thesystem vent in the reactor system 18 after serving as a counter-flow inthe gas drier 52 (FIG. 2).

With this arrangement, the continuous process total oxidation of carbonsystem 10 supplies the sample water and oxidizing agent such as sodiumpersulfate or potassium persulfate to the reactor system together with acarrier gas such as air. This system mixes the carrier gas, oxidizingagent and water sample turbulently and supplies it through a large bulkflow section for slow linear movement during a residence time adequatefor mixing them, and then, forces the water at the same volumetric flowrate but with very rapid linear velocity along a shallow helical pathclose to the UV source for exposure to UV light, heating and mixing atrapid velocity and close proximity to the ultraviolet light source. Thereactor repeats this process until the total organic carbon is oxidizedas the liquid moves vertically upwardly along a single ultraviolet lampto the top, where the carbon dioxide flows into a detector fordetection, measuring and reporting.

In FIG. 2, there is shown a schematic diagram of the water source 12,the additive source 14, the air source 16, the reactor system 18 and thedetector 20 connected together as described in connection with FIG. 1.As shown in FIG. 2, the reactor system 18 includes a first gas-liquidseparator and condenser 58 serving also as a system liquid drain, asecond gas-liquid separator 50, a gas drier 52 which serves as agas-water vapor separator and an inorganic carbon sparge or scrubber 60which also includes a third gas-liquid separator as its principal parts.

As shown in FIG. 2, the sample enters the reactor system through aconduit 22 and passes through the inorganic sparge 60 which removesinorganic carbon. Such inorganic carbon sparges are known in the art andthe sparge 60 is not in itself part of the invention. The liquid, afterbeing sparged is pumped by the organic sample pump 54 with which itcommunicates through conduits into the ultraviolet reactor 56 forreaction with an oxidizing agent. The gas/liquid mixture leaving thesparge 60 passes to the trap/condenser 58 where the gas/liquid mixtureis then routed to the waste side of the gas separator 50. The gasseparator 50 vents through line 38 and drains through line 40.

An oxidizer such as for example sodium persulfate is pumped by oxidizerpump 64 through conduit 26 into the UV reactor from the source ofoxidizer 62 and carrier gas is pumped into the ultraviolet reactor 56from the carrier gas system 16. The gas flowing into the ultravioletreactor 56 vigorously mixes the oxidizer and sample water, and in aseries of stages, permits it to flow at a relatively low linear rate formixing and then through a helical very rapidly moving path around andclose to the UV lamp for reaction under the force of the catalystultraviolet light. These stages are sized to provide the proper amountof heavy exposure of UV light, mixing and separating of gas along astraight short vertical line for total oxidation of the organic carbonand removal of the total amount of carbon gases formed by oxidation.Thus, economical structure is used in a relatively short vertical heightto obtain the total organic carbon oxidation.

The gas leaving the reactor 56 is passed through a conduit to thetrap-condenser 58 at an upper location for further condensing of liquidand separation of gas. From the trap-condenser, the gas flows to the gasliquid separator 50 for further collection of liquid and from the top ofthe gas-liquid separator 50 through the Nafion tube gas drier 52. TheNafion drier includes an inner Nafion tube through which water vaporpasses selectively in a manner known in the art and a counter flow ofcarrier gas between the inner tube and an outer tube to remove the watervapor to the gas-water separator 50 for draining through conduit 40.

From the gas drier 52, the carbon dioxide moves into the detector system20. The separator 50 receives the counter flow containing gas and liquidvapore from the Nafion tube gas drier 52, a gas vent outlet below andseparated from the inlet from the UV reactor of the trap/condenser 58and from a still lower liquid drain of the trap/condenser 58. Itincludes a system drain which causes the flow of liquid to conduit 40for disposal when the liquid reaches a level lower than the top level ofthe separator 50, the top level of the separator 50 being utilized topermit the flow of gas from the reactor to the Nafion tube gas drier 52.

To supply oxidizer to the UV reactor 56, the additive source 14 includesa source of sodium persulfate or potassium persulfate or other oxidizer62 and an oxidizer pump 64 for pumping oxidizer into conduit 26 and fromthere to the UV reactor 56. The carrier gas source 16 includes a sourceof compressed gas 66, a carbon dioxide removal column 68, threetee-fittings 70, 72 and 91, three pressure regulators 74, 80 and 93, twoflow meters 76 and 82, a flow switch 84, a capillary tube 86 and a checkvalve 88. The compressed gas 66 communicates through a conduit to anoptional carbon dioxide removal column 68 which in turn communicatesthrough the tee-fitting 70 with two other tee-connections 72 and 91.This supplies compressed gas for use in the entire continuous processtotal oxidation of carbon system 10 (FIG. 1). The tee-connection 91supplies gas under pressure through one conduit 30 to the three-wayvalve 132 and supplies gas through the other outlet of the tee-fitting91 to the zero to five pounds per square inch regulator 93 with acontrolled flow rate of 250 cubic centimeters per minute through asecond conduit 32 to the detection system 20 to purge the atmospheresurrounding the IR detector 130 of CO₂.

The other tee-connection 72 supplies gas: (1) through one conduit to thezero to 10 pounds per square inch regulator 74 and from there throughthe flow meter 76 through conduit 24 into the sample supplying system 12for creating turbulence in the sparge 60; and (2) through a zero to 30pounds per square inch pressure regulator 80, a flow meter 82, a flowswitch 84, the capillary tube 86 and the check value 88 in that order tothe ultraviolet reactor 56 through conduit 28 to provide turbulencetherein.

To supply sample to the ultraviolet reactor, the water sample source 12includes as its principal parts a source of sample 92, a source pump 90for pumping the sample, a loss of flow detection detector 94, a manualthree-way valve 98, a source of manual sample 96, an electric two-wayvalve 100, a tee-fitting 110, a feed pump 108 and a second tee-fitting126. These elements permit samples from the source 92 to be pumped bysource pump 90 through the loss of flow detection detector 94, themanual three-way valve 98, the electric two-way valve 100, thetee-fitting 110, the feed pump 108 and the tee-fitting 126 to theconduit 22 for supplying the sample liquid and carrier gas to theinorganic carbon sparge 60.

The source pump 90 pumps liquid from a source through the loss-of-flowdetector 94 and back to the source of liquid. The loss-of-flow detector94 permits the turning off of the system in the absence of liquid sampleflowing to avoid heat damage and also permits liquid sample to flowthrough it to the feed pump 108. The manual sample source 96 may providea sample instead of the pump 90 from the manual three-way valve 98 byswitching between a first position which is an off position or from aposition communicating with loss of detection detector 94 to a positionconnected to the manual sample 96. The electric two-way valve providesover-all control for the flow through the tee-fitting 110 to the feedpump 108 for application through the tee-fitting 126 to the conduit 22.

To provide cleaning solution, de-ionizing water or calibrating solution,a three-into-one normally closed selector valve 124 has its inletsconnected to the clean solution source 102, a source of de-ionized water104 and a calibration solution 106. Its outlet, is connected to thetee-fitting 110 so that in combination with two-way valve 100, the feedpump may draw from sample, clean solution, de-ionized water orcalibration solution through the tee-fitting 110. Similarly, acid may besupplied to the tee-fitting 120 from an acid source 114 to adjust the pHof the sample to a level sufficiently low to release carbon dioxide fromthe sample as a gas by the acid pump 116 for application to anotherinlet of the tee-fitting 126 and eventual application to the conduit 22.The tee-fitting 120 similarly can receive gas through conduit 24, theflow switch 112 and the check valve 121 for application through thetee-fitting 126 to the outlet conduit 22 from the air supply 16. Adilution fluid may be connected through the source of dilution fluid 122and the dilution pump 118 through a tee-fitting 126A which is optionallyincluded in series with the tee-fitting 126 so as to dilute liquid fromthe feed pump 108.

The detection system 20, includes an infrared detector 130 and athree-way valve 132. The infrared detector 130 includes a sample cell134 to permit infrared detection and measurement of carbon dioxidewithin the sample cell 134 in a manner known in the art. Carbon dioxideafter detection may be vented through the vent 136 and a signal appliedthrough cable 48 to the computer 44 for analysis.

The carbon dioxide is applied from the gas drier 52 through the conduit34 (FIG. 2) into the normally open position of the three-way valve 132.The three-way valve, besides having a normally open position, is alsoconnected at the normally closed position to the conduit 30 from thesource of gas at the tee-joint 91 to supply CO₂ free gas under pressurethrough the valve 132 and the sample cell 134 for use in calibrating theinfrared detector 130. For purging purposes, the infrared detector 130communicates with the gas tube drier 52, conduit 32 (FIG. 2) andreceives a purging gas from the regulator 93.

In FIG. 3, there is shown an elevational view of a control panel 140showing the computer 44 with a keyboard 142, flowmeter displays shown at76 and 82, the power switch 150, the ultraviolet reactor 56 (in acabinet), power switches and indicators 152 and 154 for UV reactor andpump power respectively, the trap-condenser 58, the sparge 60, sourceselector valve 98 for selection of manual sample source or continuoussample source, the pumps 90, 64 (with 116 stacked behind it) 54 and 108are all visibly shown on the front of the panel with the appropriateconduits connecting the ultraviolet reactor 56, the trap/condensor 58and the scrubber 60. With this arrangement, convenient control throughthe computer panel is provided and the basic operation and indicatorsmay be easily monitored.

In FIG. 4, there is shown a fragmentary broken away view of the UVreactor 56 having a generally cylindrical reactor bottom 154, a firstreactor body 156, a second reactor body 158, a reactor top 160 and aultraviolet lamp 150 having electrical conductors 152 connected to it.Several other reactor bodies may be included in this sequence.

With this arrangement, the reactor bottom 154 has a plurality of ports,with three being used in the preferred embodiment. One port is adaptedto receive the sample and one port adapted to receive oxidizers, and oneto receive carrier gas. The oxidizer may be potasium persulfate, sodiumpersulfate, ozone or others.

The three port openings are shown at 162, 164 and 166, spacedcircumferentially around the end of the member to permit injection ofliquids radially inwardly to a hollow center above the bottom of thelamp. At the bottom is an opening 168 internally threaded to receive aplug for sealing the bottom end or a mounting member for mounting thereactor and sealing the bottom end. At the top end is a shoulder endingin a reduced diameter externally threaded upwardly extending tube 170adapted to receive an "O" ring and be threaded into the first bodymember 156 with an opening extending therethrough for the passage ofliquid and to receive the ultraviolet lamp 150 which extends downwardlythrough the center for providing ultraviolet light as a catalyst to theliquid. The sample is irradiated by the lamp and the sample, air andoxidizer introduced in the ports after the start of irradiation.

In a first embodiment of reactor 56, shown in FIGS. 4-10, the flow pathis broken into a plurality of parts in series with each other andsharing the UV lamp. Each section includes a helical path and aresidence chamber. The residence chamber provides further mixing,reaction time and breaking of air bubbles. The residence chambers are oflarger volume per vertical unit of height along the UV lamp.

A second embodiment includes one continuous helix without residencechambers. It is less expensive, under some circumstances, to manufactureand use. In the second embodiment, horizontal mixing of the liquid ismaximized and vertical mixing minimized by permitting the escape of gasvertically or using other means to control the size of gas bubbles thatotherwise consolidate into larger and larger bubbles as the gas andliquid moves upwardly.

To provide for mixing of fresh oxidizers with the high carbon waterentering at the bottom in the embodiment 56 of FIGS. 4-10, the firstreactor body 156 includes a relatively wide and long inner residencetime chamber 172 having high volume between the walls of the firstreactor body and the central ultraviolet lamp to provide relatively slowlinear motion in stable condition during mixing with the high organiccarbon liquid and high oxidizer concentrations. The size of the innerchamber is chosen in accordance with the volumetric rate of flow of thiscontinuous reactor member and the expected organic carbon of the liquidto provide adequate mixing before reaching an end portion of the firstbody member.

Near the end of the first reactor body which is above the reactor bottom154, is a narrowed section having internal grooves within it forming anupwardly extending helix as shown at 174 and similarly having externalthreads 176 for engaging internal threads in the second body member 158,the connecting sections being connected with "O" rings for sealing. Anultraviolet lamp fits relatively tightly against the walls of the narrowhelix areas so that the liquid moving upwardly in the ultravioletreactor 56 in the narrowed section between the first reactor body 156and the second reactor body 158 increases its linear speed to passthrough the narrow helical passageway thus creating further turbulance,forcing the liquid closely against the ultraviolet lamp and increasingits path length along the helix to cause high intensity radiation withthe catalytic ultraviolet light and mixing for reaction.

The liquid next passes into a second enlarged residence chamber in thesecond body member 158. This residence chamber may be smaller or largerthan the lower chamber in the first reactor body 156. The diameter ofresidence chambers should be: (1) at least one and one-quarter times thediameter of the helix between residence chambers; and (2) at least twotimes the depth of said helical grooves.

The ability of the sections to be separated enables separate sizingdepending on the expected carbon content of the liquid and permits morereactant or other additives to enter through separate ports into thesecond chamber if desired. More importantly the tailoring of the amountof oxidizer to match expected carbon content can be addressed anew aswell as the residence time of moving through the larger chamber bychanging the configuration, because the size of the residence chambercan be indepenently selected for insertion in the column. Any number ofstages may be incorporated prior to the reactor top 160 which includes afinal stage and the outlet ports for receiving reacted liquid and theseparated carbon dioxide for measuring.

In FIG. 5 there is shown a longitudinal sectional view of a reactor 56including the reactor bottom 154 showing one port 164 and the threadedbottom end 168 to receive a plug, the first reactor body 156 with itshelical reaction section 174 and threaded narrow end 176, the secondreactor body 158 and a third and fourth reactor bodies 178 and 180connected together with the reactor top 160 being connected to thereactor body 180. The first, second and third reactor bodies are shownwithout a port but the fourth is shown having a radial port 198 tosupply additional reactants or air or to provide for the insertion of atemperature probe for monitoring reaction temperature. Any of themembers may have a radial port for further treatment and the sizes ofthe sections may be adapted based on experience relating to the carboncontent and the carrier gas passing through the residence chamber. Atthe top member 160 is a threaded opening 182 adapted to receive a nutfor holding the UV lamp extending downwardly through the center of thereactor to a location adjacent to the plug that fits in the opening 168.

Generally, the residence chambers have a diameter: (1) of at least oneand one-half times the diameter of the helix formed by the helicalgroves; and (2) at least four times the depth of the helical groove.

While in the preferred embodiment, a single ultraviolet lamp isutilized, multiple lamps could be utilized. However, it is desirable toutilize only one lamp for convenience in assembly and for reduction incost since the ultraviolent lamps are a relatively expensive component.It is desirable to have a single upwardly extending column rather thanbroken columns since a single column reduces the opportunities for theescape of carbon dioxide gas prior to being measured.

In FIG. 6 there is shown a sectional view of a reactor top 160 havinginternal threads shown at 192 for connecting to the prior section a port190 through which the liquid and gas leave and a threaded port 182 forreceiving the ultraviolet lamp and ultraviolet lamp nut for insertingthe ultraviolet lamp downwardly. The generally cylindrical tubular topin the preferred embodiment has approximately a two inch height with a0.58 inch tapped port 182 in its top ending in a shoulder defining acircular opening extending downwardly 0.375 inches to the radial port190. The overall outer diameter is approximately 1.5 inches. An "O" ringis adapted to be positioned in the annular opening 194 for sealing thetop member to the next lowest member.

In FIGS. 7 and 8 there are shown a transverse section and a longitudinalsection respectively of the bottom member 154 showing the ports 162, 164and 166 as well as the bottom member for receiving a plug shown at 168.The bottom member has a general height in the preferred embodiment of1.9 inches, an outer circumference of 1.5 inches, with external 1-12UNF-2B type threads 170 matching the internal threads of the firstreactor body.

In FIG. 9, there is shown a reactor body having a port 198 similar tothe fourth reactor body 180 in FIG. 5. Reactor bodies may not have portsor may have one or more ports and are selected for a reactor assembly inaccordance with size and the need for a port depending on the organiccarbon content of the liquid being tested and the design for measuringtotal organic carbon. The reactor body 180 has an outer dimension of 1.5in this particular column to match the other members of the column andinternal threads on one side to match the external threads on the priormember receiving the helical reaction section. Similarly, on its upperend it has external threads and an internal helix 200 for causing theliquid to rapidly flow along the helix in close proximity to theultraviolet lamp.

The helix has a pitch of four with grooves 1/8 inch wide separated bylands of 1/8 inch that block the passage of the liquid between groovesto cause the liquid to flow along a helical path 1/8 inch wide, a pitchof four and a depth of approximatley 1/8 inch. The helical path isapproximately 1.19 inches in length along its vertical axis. Theresidence chamber is approximately 0.62 inches for this particularreaction body and it includes a threaded portion to provide a combinedresidence section of approximately 1.62 inches. It has an overall lengthof 2.81 inches and an inner diameter of the cavity of 0.875 inches whichreceives the ultraviolet lamp which has a diameter of 0.354 inches.

In FIGS. 10 and 11 there are shown a top view and an elevational view ofthe reactor assembly 56 having heater strips 202 and 204 for controllingthe temperature within the reaction chamber and mounted outside of aheat distribution tube 206. Clamps 208, 210, 212 and 214 are provided tocompress the heat distribution tube 206 onto the assemlege of reactorsections shown in FIG. 5. A temperature probe 216 may be provided tomeasure the temperature within the reactor and thus provide feedbackcontrol to the temperature strips for maintaining the temperature at adesirable level. The feedback circuitry may be connected through thecomputer 44 (FIGS. 1 and 3).

In FIG. 12, there is shown a 1/8 inch thick tube 300 serving as areactor shell for the purposes of providing protection and improving theappearance of the ultraviolet reactor. The upper and lower ends of thetube 300 are opened to receive conduits and electrical connections wherenecessary. The temperature probe 216 which is a thermistor is shownwithin the shell.

In FIG. 13, there is shown an elevational view of the ultraviolet lamp150 having an ultraviolet lamp nut 302 for threading into the opening182 (FIG. 5) and extending downwardly through the reactor to provideultraviolet light. In the preferred embodiment it is a low pressuremercury ultraviolet lamp having a lighted length of 151/4 inches, a tubeouter diameter of 0.354 inches with a quartz glass envelope. It iscommercially available and has a starting voltage of 3400 volts ACnominal and an operating voltage of 500 volts AC with a startingfrequency of 10 KHz (kilohertz) and an operating frequency of 38 KHz.The operating current range is between 15 and 50 milliamperes.

In FIGS. 14, 15 and 16 there are shown a side elevational view, an endelevational view and a top view respectively of the loss of liquiddetector 94 having a hollow body 160 and inlet port 162, an outlet port164, and a fixed drain port 166. Sample flows through the inlet port 162into the hollow body and out the outlet port 164 by the feed pump 108(FIG. 3). The drain port 166 removes liquid which in the preferredembodiment varies between two and 37 milliliters (ml) per minutedepending upon the carbon content of the sample, and is drawn bygravity. The sample flowing through includes approximately 39 ml perminute flowing into the loss of liquid detector and a portion out of theloss of liquid detector in a recirculated manner under the control ofthe source pump 90 (FIG. 2) and fixed drain 166.

As best shown in FIG. 14 and FIG. 15, the wall of the body 160 includesa cylindrical recess 170 (see FIG. 14 for its location) and a supportpost 172. As shown in the exploded view of FIG. 17, a thermistor 174 isadapted to fit into the opening 170 with electrical lead lines 176 and178 extending therefore. The thermistor is held in place by theupstanding post 172, clamp 180 together with a shrink wrap packing 182which hold the conductors 176 and 178 in place and adhesive placedinside recess 170.

In operation, if the sample liquid is interupted, the housing 160 heatsup from the current through the thermistor and the thermistor 174detects the temperature change. This detection results in a currentchange through conductors 176 and 178 which supplies a signal throughthe computer to shut down the unit. In the preferred embodiment, theinsulation about the thermistor is such that it reaches its overheatedcondition within ten minutes without water cooling the thermistor andbody but this time can be controlled by the amount of insulation. Whileliquid is flowing however, the flow of liquid through the body cools thebody of the detector and thus maintains the temperature within a regionsuitable for operation.

On the other hand, if flow stops, liquid drains from the body 160 of theloss of liquid detector, the thermistor heats up and a signal isprovided, preventing the overheating of the entire unit and possibledamage.

In FIG. 18, there is shown in a fragmentary elevational view anembodiment of ultraviolet reactor 56A that operates in a manner similarto the embodiment 56 of FIGS. 4-10 but has been simplified so that theentire reactor 56A includes only a single integrally formed glass tube156A with a single integrally formed helix 174A instead of the threeindividual sections including the residence chambers, helical portionsand their ports. To enable the single section to operate properly,control must be exercised over the size of the gas bubbles that flowthrough the tube outside of the ultraviolet lamp along the helical path.In the preferred embodiment, this is accomplished by permitting gas toescape vertically upwardly through a space between the inner diameter ofthe helix and the ultraviolet lamp. This helix is large enough to permithorizontal mixing but shaped to reduce vertical mixing. Very littleliquid moves vertically through the narrow space between the outerdiamater of the helix and the glass cylinder and substantially all isforced to move vertically as it moves along the helix. The liquid in thepreferred embodiment is prevented from vertical movement falling throughthe gap between the outside of the helix 174A and the glass cylinder156A because of surface tension and the narrowness of the gap. Ofcourse, the gap could be formed in other places such as between thehelix and the outer glass tube or both between the ultraviolet lamp andthe tube or special tubular escape vents could be provided along thetube closed at the bottom to prevent the fall of water or many otherpossible configurations could be used.

In the preferred embodiment, the bubbles reach equilibrium at betweenone-third and two-thirds of the vertical distance. They are kept smallenough along the helix to avoid plug flow pushing liquid ahead of them.The air gap between the outside of the helix and the glass container orother air escape paths reduce bubble size and the helix causeshorizontal mixing and reduces vertical mixing. For efficiency, thetemperature is also maintained at 85 degrees centigrade although it canbe maintained within a wide range of approximately 60 degrees centigradethrough 100 degrees centigrade when the carrier gas for the carbondioxide is air. Other measures might be taken to break larger bubbles,most of which are well known such as ultrasound or formations that breakbubbles apart or surfactant when vents with closed bottoms are used. Inthe preferred embodiment, the reactor is approximately 13.25 inches longand approximately 11/2 inches in outer diameter. The glass helix issolid pyrex glass having 21 turns of 0.28 inch diameter glass along itslength with a space of 0.60 inches between turns to provide a 20 to 70percent pitch with 40 percent being optimum. There is a radial air gapbetween the walls of the helix and the ultraviolet lamp of 0.130 in thepreferred embodiment although the gap may be between 0.090 and 1.0inches.

For reliable operation, gas leaks at the top of the cap must be avoided.In FIG. 19, there is shown a cross sectional view of a cap 154A having abore 190A with a circular annular O-ring 194A fitted within a radiallyoutwardly threaded portion 192A that threads on the top of the glasstube 156A instead of the arrangement shown in FIG. 6. The annular ringreceiving the O-ring 194A provides a secure gas tight connection that isreliable. The annular cavity is slightly larger than needed toaccommodate the diameter of the ring which extends above the top and canbe tightly compressed to reliably form a seal.

From the above description, it can be understood that, the carbonanalyzing apparatus and technique of this invention has severaladvantages, such as for example: (1) it is economical to construct andit may require only one ultraviolet lamp; (2) it reduces the amount ofprematurely lost carbon dioxide because it may be formed as a singlevertical column to permit collection of carbon dioxide at the top of thecolumn; and (3) it provides relatively easy adjustment to maintain abalance between: (a) the time for mixing the oxidizing agents, carriergas and samples; (b) the reaction time, (c) the amount and time ofirradiation; and (d) the amount of oxidizing agent required.

More specifically in one embodiment, the use of separate residencereservoirs of relatively large size minimizes the interaction betweenthe reaction stages as the liquid and gas components rise through theultraviolet reactor assembly. This minimizes the possibility of liquidwith organic carbon content that is high being mixed with only a smallinsufficient amount of unspent oxidizer. It provides a greateropportunity for balancing the amount of oxidizers and unreacted organiccarbon to improve efficiency.

The separate residence time reservoirs also allow for addition ofreagents of intermediate points in the reaction. This may be necessarywhen high carbon content in the liquid exhausts the oxygen in thereagents before the carbon is oxidized. Moreover, it permits adjustmentfor other compounds such as sodium chloride that provide ions resultingin side reaction that use up oxygen. Thus the reaction may be driven tocompletion not withstanding the presence of other compounds.

The use of a plurality of separate compartments which may be threadedtogether also permits ease of manufacture and maintenance and provideseasy variety of the construction of the column so as to reduce the costand improve its ability to perform under different circumstances.

In a second embodiment, the provision of an air escape sized to breaklarger bubbles and a helix shaped to reduce vertical mixing and maximizehorizontal mixing along the helical path thus permitting side to sidemixing action as the liquid moves from the bottom to the top providestotal oxidation of the organic carbon.

While a preferred embodiment of the invention has been described in somedetail, many modifications and variations in the embodiment areposssible within the light of the above teachings. Therefore, it is tobe understood, that within the scope of the appended claims, theinvention may be practiced other than as specifically described.

What is claimed is:
 1. A method of measuring total organic carboncontent comprising the steps of:applying a sample liquid to asubstantially continuous vertical tubular column; oxidizing carbon inthe sample liquid as it flows along the substantially continuousvertical tubular column; the step of oxidizing including the steps ofproviding a substantially continuous curvilinear path adjacent to anultraviolet source between the ultraviolet lamp and the inner wall ofthe continuous tubular vertical column for slow linear vertical movementof the sample liquid while mixing; reducing vertical mixing of thesample liquid while maximizing horizontal mixing; and determining thecarbon dioxide released from the liquid sample.
 2. A method of measuringtotal organic carbon content in accordance with claim 1 in which thestep of oxidizing includes the steps of:mixing the sample liquid with atleast one oxidizer in the substantially continuous curvilinear path; andmaintaining the size of bubbles substantially smaller than the size ofthe substantially continuous curvilinear path.
 3. A method according toclaim 1 wherein the substantially continuous curvilinear path issufficently narrow and long to oxidize substantially the entire carboncontent of the liquid.
 4. A method according to claim 1 wherein theliquid is caused to flow upwardly along the substantially continuouscurvilinear path.
 5. A method according to claim 1 wherein the liquid iscaused to flow along a substantially continuous helical path.
 6. Amethod according to claim 2 in which the step of maintaining the size ofbubbles includes the step of permitting the escape of air in largerbubbles from the substantially continuous curvilinear path.
 7. A methodaccording to claim 6 further including the step of blocking the escapeof carbon dioxide from a gas tight cap at the top of the column.